Over the years, the transport of toxic and hazardous gases, such as nitrogen, argon, hydrogen, oxygen, silane, phosphine, arsine, plus various mixed gases, via piping systems, has presented a serious problem for engineers, contractors and others who use or effect transportation of these gases. When piping systems are used to transport such gases or fluids from one point to another there always exists the possibility of a leak occuring in the piping system, thereby allowing hazardous or toxic gases to escape, thus presenting the possible risks of death or sickness resulting from inhalation of the gases by persons near the piping system or explosion, should the escaped incendiary gases ignite.
Prior art methods attempting to solve this problem use coaxial piping systems having a conduit or pipe for transporting the hazardous fluids contained inside an outer conduit so that should a leak occur at the inner transporting pipe the fluids would be contained in the volume between the inner conduit and the outer conduit. This method, however, has presented many drawbacks in that when bending such a coaxial system to conform to the desired path of the piping system, the inner pipe often crimps or buckles at the elbow of the bend Also, fracture of the inner conduit due to stress caused by vibrations occurs in such prior art coaxial piping systems because the inner conduit is suspended inside the outer tube, and thus vibrates and eventually fractures or cracks at stress points.
Another drawback relates to the method for alleviating the problems occurring as a result of leakage In the prior art, when a leak occurs in such a system, the hazardous fluid or gas emanates from the point of the leak into the volume between the inner conduit and the outer conduit, thereby creating a pocket of hazardous gas. In order to flush this gas from the volume between the inner and outer conduit a purging gas must be sent through the volume between the inner conduit and the outer conduit. However, because the leaking hazardous or toxic gas collects and forms a pocket of gas around the leak, as it is purged from the system the hazardous gas emanates at an output of the coaxial system in a somewhat concentrated form. Such an output of a relatively concentrated pocket of hazardous gas presents the aforementioned dangerous possibilities of fatal or otherwise dangerous inhalation or explosion or fire.